Diene cyclization using ruthenium and osmium carbene complexes

ABSTRACT

Disclosed are ruthenium and osmium carbene compounds which are stable in the presence of a variety of functional groups and which can be used to catalyze olefin metathesis reactions on unstrained cyclic and acyclic olefins. Specifically, the present invention relates to carbene compounds of the formula ##STR1## wherein: M is Os or Ru; R and R 1  are independently selected from hydrogen and functional groups C 2  -C 20  alkenyl, C 2  -C 20  alkynyl, C 1  -C 20  alkyl, aryl, C 1  -C 20  carboxylate, C 2  -C 20  alkoxy, C 2  -C 20  alkenyloxy, C 2  -C 20  alkynyloxy, aryloxy, C 2  -C 20  alkoxycarbonyl, C 1  -C 20  alkylthio, C 1  -C 20  alkylsulfonyl or C 1  -C 20  alkylsulfinyl; each optionally substituted with C 1  -C 5  alkyl, a halogen, C 1  -C 5  alkoxy or with a phenyl group optionally substituted with a halogen, C 1  -C 5  alkyl or C 1  -C 5  alkoxy; X and X 1  are independently selected from any anionic ligand; and L and L 1  are each trialkyl phosphine ligands where at least one of the alkyl groups on the phosphine is a secondary alkyl or a cycloalkyl. A broad array of metathesis reactions are enabled including ring-opening metathesis polymerization of cyclic olefins, ring closing metathesis of acyclic dienes, cross metathesis involving at least one acyclic or unstrained cyclic olefin, and depolymerization of unsaturated polymers.

ORIGIN OF INVENTION

The U.S. Government has certain rights in this invention pursuant toGrant No. CHE-8922072 awarded by the National Science Foundation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a divisional of application Ser. No. 08/282,827, filed Jul. 29,1994, which is a continuation-in-part application of application Ser.No. 08/106,292 filed Aug. 13, 1993 now issued as U.S. Pat. No. 5,342,909which is a divisional application of Ser. No. 07/863,606, filed Apr. 3,1992 now issued as U.S. Pat. No. 5,312,940.

BACKGROUND OF THE INVENTION

This invention relates to highly active and stable ruthenium and osmiummetal carbene complex compounds and their use as catalysts in olefinmetathesis reactions.

During the past two decades, research efforts have enabled an in-depthunderstanding of the olefin metathesis reaction as catalyzed by earlytransition metal complexes. In contrast, the nature of the intermediatesand the reaction mechanism for Group VIII transition metal catalysts hasremained elusive. In particular, the oxidation states and ligation ofthe ruthenium and osmium metathesis intermediates are not known.

Many ruthenium and osmium metal carbenes have been reported in theliterature (for example, see Burrell, A. K., Clark, G. R., Rickard, C.E. F., Roper, W. R., Wright, A. H., J. Chem. Soc., Dalton Trans., 1991,Issue 1, pp. 609-614). However, the discrete ruthenium and osmiumcarbene complexes isolated to date do not exhibit metathesis activity tounstrained olefins. (Ivin, Olefin Metathesis pp. 34-36, Academic Press:London, 1983).

SUMMARY OF THE INVENTION

The present invention relates to ruthenium and osmium carbene compoundswhich are stable in the presence of a variety of functional groups andwhich can be used to catalyze olefin metathesis reactions on unstrainedcyclic and acyclic olefins.

Specifically, the present invention relates to carbene compounds of theformula ##STR2## wherein:

M is Os or Ru;

R and R¹ are independently selected from hydrogen or a hydrocarbonselected from the group consisting of C₂ -C₂₀ alkenyl, C₂ -C₂₀ alkynyl,C₁ -C₂₀ alkyl, aryl, C₁ -C₂₀ carboxylate, C₂ -C₂₀ alkoxy, C₂ -C₂₀alkenyloxy, C₂ -C₂₀ alkynyloxy, aryloxy, C₂ -C₂₀ alkoxycarbonyl, C₁ -C₂₀alkylthio, C₁ -C₂₀ alkylsulfonyl and C₁ -C₂₀ alkylsulfinyl;

X and X¹ are independently selected from any anionic ligand; and

L and L¹ are each trialkyl phosphine ligands where at least one of thealkyl groups on the phosphine is a secondary alkyl or a cycloalkyl.

In a preferred embodiment, the hydrocarbon is selected from the groupconsisting of C₁ -C₅ alkyl, halogen, C₁ -C₅ alkoxy and a phenyl group.

In an alternative embodiment, the phenyl group is optionally substitutedwith halogen, C₁ -C₅ alkyl and C₁ -C₅ alkoxy.

In a preferred embodiment, all of the alkyl groups of the trialkylphosphine are either a secondary alkyl or a cycloalkyl. In a morepreferred embodiment, the alkyl groups are either isopropyl, isobutyl,sec-butyl, neopentyl, neophyl, cyclopentyl or cyclohexyl.

The present invention also relates to metathesis coupling of olefinscatalyzed by the carbene compounds of the present invention. The highlevel metathesis activity of the ruthenium and osmium carbene compoundsof the present invention enable these compounds to coordinate with andcatalyze metathesis reactions between all types of olefins. By contrast,previous non-carbene ruthenium and osmium metathesis catalysts are onlyable to catalyze metathesis reactions involving highly strained olefins.As a result, a broad array of metathesis reactions are enabled using thecarbene compounds of the present invention that cannot be performedusing less reactive catalysts.

Examples of metathesis olefin coupling reactions enabled by theruthenium and osmium carbene compounds of the present invention include,but are not limited to, ring-opening metathesis polymerization ofstrained and unstrained cyclic olefins, ring closing metathesis ofacyclic dienes, cross metathesis reactions involving at least oneacyclic or unstrained cyclic olefin and depolymerization of olefinicpolymers.

DETAILED DESCRIPTION

The present invention relates to new highly active and stable rutheniumor osmium carbene compounds which can be used to catalyze olefinmetathesis reactions.

Specifically, the present invention relates to carbene compounds of theformula ##STR3## wherein:

M is Os or Ru;

R and R¹ are independently selected from hydrogen; C₂ -C₂₀ alkenyl, C₂-C₂₀ alkynyl, C₁ -C₂₀ alkyl, aryl, C₁ -C₂₀ carboxylate, C₂ -C₂₀ alkoxy,C₂ -C₂₀ alkenyloxy, C₂ -C₂₀ alkynyloxy, aryloxy, C₂ -C₂₀ alkoxycarbonyl,C₁ -C₂₀ alkylthio, C₁ -C₂₀ alkylsulfonyl or C₁ -C₂₀ alkylsulfinyl; eachoptionally substituted with C₁ -C₅ alkyl, halogen, C₁ -C₅ alkoxy or witha phenyl group optionally substituted with halogen, C₁ -C₅ alkyl or C₁-C₅ alkoxy;

X and X¹ are independently selected from any anionic ligand; and

L and L¹ are each trialkyl phosphine ligands where at least one of thealkyl groups on the phosphine is a secondary alkyl or a cycloalkyl.

In a preferred embodiment, all of the alkyl groups of the trialkylphosphine are either a secondary alkyl or a cycloalkyl. In a morepreferred embodiment, the alkyl groups are either isopropyl, isobutyl,sec-butyl, neopentyl, neophyl, cyclopentyl or cyclohexyl.

The high level metathesis activity of the carbene compounds of thepresent invention is observed when L and L¹ are alkyl phosphines wherethe carbon backbone of at least one alkyl group of the alkyl phosphineis a secondary alkyl or cycloalkyl. Substitution of the secondary alkyland cycloalkyl with additional carbon moieties and/or other functionalgroups are intended to be included with the terms secondary alkyl andcycloalkyl.

The present invention also relates to metathesis coupling of olefinscatalyzed by the carbene compounds of the present invention. The highlevel metathesis activity of the ruthenium and osmium carbene compoundsof the present invention cause these compounds to coordinate with andcatalyze metathesis reactions between all types of olefins. By contrast,previous non-carbene ruthenium and osmium metathesis catalysts are onlyable to catalyze metathesis reactions involving strained olefins. As aresult, a broad array of metathesis reactions are enabled using thecarbene compounds of the present invention that cannot be performedusing less reactive catalysts.

Examples of reactions enabled by the ruthenium and osmium carbenecompounds of the present invention include, but are not limited to,ring-opening metathesis polymerization of strained and unstrained cyclicolefins, ring closing metathesis of acyclic dienes, cross metathesisreactions involving at least one acyclic or unstrained cyclic olefin anddepolymerization of olefinic polymers.

The carbene compounds disclosed in the present invention, as well asthose disclosed in U.S. Pat. No. 5,312,940, are the only Ru and Oscarbene complexes known to date in which the metal is formally in the +2oxidation state (the carbene fragment is considered to be neutral), havean electron count of 16, and are pentacoordinate. Unlike most metathesiscatalysts presently known which are poisoned by functional groups, thecarbene compounds of the present invention are stable in the presence ofa wide variety of functional groups including alcohol, thiol, ketone,aldehyde, ester, ether, amine, amide, nitro acid, carboxylic acid,disulfide, carbonate, carboalkoxy acid, isocyanate carbodiimide,carboalkoxy, and halogen functional groups. As a result of theirstability in the presence of functional groups, these catalysts may beemployed in protic and aqueous solvents as well as mixtures of protic,aqueous, and/or organic solvents.

With regard to ligands R and R¹ :

alkenyl can include vinyl, 1-propenyl, 2-propenyl; 3-propenyl and thedifferent butenyl, pentenyl and hexenyl isomers, 1,3-hexadienyl and2,4,6-heptatrienyl, and cycloalkenyl;

alkenyloxy can include H₂ C═CHCH₂ O, (CH₃)₂ C═CHCH₂ O, (CH₃)CH═CHCH₂ O,(CH₃)CH═C(CH₃)CH₂ O and CH₂ ═CHCH₂ CH₂ O;

alkoxy can include methoxy, ethoxy, n-propyloxy, isopropyloxy and thedifferent butoxy, pentoxy and hexyloxy isomers;

cycloalkoxy can include cyclopentyloxy and cyclohexyloxy;

alkoxyalkyl can include CH₃ OCH₂, CH₃ OCH₂ CH₂, CH₃ CH₂ OCH₂, CH₃ CH₂CH₂ CH₂ OCH₂ and CH₃ CH₂ OCH₂ CH₂ ; and

alkoxycarbonyl can include CH₃ OC(═O); CH₃ CH₂ OC(═O), CH₃ CH₂ CH₂ OC(═O), (CH₃)₂ CHOC(═O) and the different butoxy-, pentoxy- orhexyloxycarbonyl isomers;

alkyl can include methyl, ethyl, n-propyl, i-propyl, or the severalbutyl, pentyl or hexyl isomers and cycloalkyl isomers;

alkylsulfinyl can include CH₃ SO, CH₃ CH₂ SO, CH₃ CH₂ CH₂ SO, (CH₃)₂CHSO₂ and the different butylsulfinyl, pentylsulfinyl and hexylsulfinylisomers;

alkylsulfonyl can include CH₃ SO₂, CH₃ CH₂ SO₂, CH₃ CH₂ CH₂ SO₂, (CH₃)₂CHSO₂ and the different butylsulfonyl, pentylsulfonyl and hexylsulfonylisomers;

alkylthio can include, methylthio, ethylthio, and the severalpropylthio, butylthio, pentylthio and hexylthio isomers;

alkynyl can include ethynyl, 1-propynyl, 3-propynyl and the severalbutynyl, pentynyl and hexynyl isomers, 2,7-octadiynyl and2,5,8-decatriynyl;

alkynyloxy can include HC═CCH₂ O, CH₃ C═CCH₂ O and CH₃ C═CCH₂ OCH₂ O;

aryl can include phenyl, p-tolyl and p-fluorophenyl;

carboxylate can include CH₃ CO₂ CH₃ CH₂ CO₂, C₆ H₅ CO₂, (C₆ H₅)CH₂ CO₂ ;

cycloalkyl can include cyclopentenyl and cyclohexenyl.

diketonates can include acetylacetonate and 2,4-hexanedionate;

"halogen" or "halide", either alone or in compound words such as"haloalkyl", denotes fluorine, chlorine, bromine or iodine;

The anionic ligands X and X¹ may be any ligand which when removed from ametal center in its closed shell electron configuration has a negativecharge. The critical feature of the carbene compounds of this inventionis the presence of the ruthenium or osmium in the +2 oxidation state(the carbene fragment is considered to be neutral), an electron count of16 and pentacoordination. A wide variety of anionic ligands, X and X¹can be used where the carbene compound will still exhibit its catalyticactivity.

With regard to the R, R¹, X and X¹ ligands, a preferred embodiment ofthe carbene compounds of the present invention is a compound where:

R and R¹ are independently selected from hydrogen, vinyl, C₁ -C₁₀ alkyl,aryl, C₁ -C₁₀ carboxylate, C₂ -C₁₀ alkoxycarbonyl, C₁ -C₁₀ alkoxy,aryloxy, each optionally substituted with C₁ -C₅ alkyl, halogen, C₁ -C₅alkoxy or with a phenyl group optionally substituted with halogen, C₁-C₅ alkyl or C₁ -C₅ alkoxy; and

X and X¹ are independently selected from halogen, hydrogen, diketonates,or C₁ -C₂₀ alkyl, aryl, C₁ -C₂₀ alkoxide, aryloxide, C₂ -C₂₀alkoxycarbonyl, arylcarboxylate, C₁ -C₂₀ carboxylate, aryl or C₁ -C₂₀alkylsulfonate, C₁ -C₂₀ alkylthio, C₁ -C₂₀ alkylsulfonyl, C₁ -C₂₀alkylsulfinyl, each optionally substituted with C₁ -C₅ alkyl, halogen,C₁ -C₅ alkoxy or with a phenyl group optionally substituted withhalogen, C₁ -C₅ alkyl or C₁ -C₅ alkoxy.

In a further preferred embodiment,

R and R¹ are independently selected from hydrogen; vinyl, C₁ -C₅ alkyl,phenyl, C₂ -C₅ alkoxycarbonyl, C₁ -C₅ carboxylate, C₁ -C₅ alkoxy,phenoxy; each optionally substituted with C₁ -C₅ alkyl, halogen, C₁ -C₅alkoxy or a phenyl group optionally substituted with halogen, C₁ -C₅alkyl or C₁ -C₅ alkoxy; and

X and X¹ are independently selected from Cl, Br, I, or benzoate,acetylacetonate, C₁ -C₅ carboxylate, C₁ -C₅ alkyl, phenoxy, C₁ -C₅alkoxy, C₁ -C₅ alkylthio, aryl, and C₁ -C₅ alkyl sulfonate; eachoptionally substituted with C₁ -C₅ alkyl or a phenyl group optionallysubstituted with halogen, C₁ -C, alkyl or C₁ -C₅ alkoxy.

In a further preferred embodiment,

R and R¹ are independently vinyl, H, Me, Ph; and

X and X¹ are independently Cl, CF₃ CO₂, CH₃ CO₂, CFH₂ CO₂, (CH₃)₃ CO,(CF₃)₂ (CH₃)CO, (CF₃) (CH₃)₂ CO, PhO, MeO, EtO, tosylate, mesylate, ortrifluoromethanesulfonate.

The most preferred carbene compounds of the present invention include:##STR4## wherein

^(i) Pr=isopropyl

Cy=cyclohexyl

The compounds of the present invention can be prepared by severaldifferent methods such as those taught in U.S. Pat. Nos. 5,312,940 and5,342,909 which are incorporated by reference herein. A one stepsynthesis of the carbene compounds of the present invention is presentedin Example 1.

The carbene complexes of the present invention have a well-definedligand environment which enables flexibility in modifying andfine-tuning the activity level, stability, solubility and ease ofrecovery of these catalysts. The electron donating ability of theneutral electron donating ligands L and L¹ of the carbene complexesinfluences the activity of the catalyst. By using more electron donatingalkyl substituents on the phosphines, one is able to conduct lessenergetically favored reactions, such as ROMP reactions on nonstrainedcycloalkenes and ring-closing metathesis reactions of acyclic dienes. Bycontrast, less reactive carbene catalysts, such as where L and L¹ areP(Ph)₃, are preferred in instances where selectivity of strained overunstrained alkenes is desired.

The solubility of the carbene compounds may be controlled by properselection of either hydrophobic or hydrophilic ligands as is well knownin the art. The desired solubility of the catalyst will largely bedetermined by the solubility of the reaction substrates and reactionproducts. It is well known in the art to design catalysts whosesolubility is distinguishable from that of the reaction substrates andproducts, thereby facilitating the recovery of the catalyst from thereaction mixture.

The carbene compounds of the present invention, because of their higherlevel of metathesis activity, are able to catalyze the metathesiscoupling of any two olefins. There are a very wide variety of reactionsthat are enabled by the ability of these carbene compounds to couple anytwo olefins.

For example, the carbene compounds of the present invention are usefulas catalysts in the preparation of a wide variety of polymers which canbe formed by the ring-opening metathesis polymerization of cyclicolefins. Unlike previous catalysts, the catalysts of the presentinvention are able to catalyze unstrained cyclic olefins such as cyclicolefins with a ring size of at least five atoms. One embodiment of thisinvention is an improved polymerization process comprising metathesispolymerization of a cyclic olefin by conducting the polymerization inthe presence of a catalytic amount of a carbene compound of the presentinvention. The polymerization reaction is exemplified for5-acetoxy-cyclooctene in the following equation: ##STR5## wherein n isthe repeat unit of the polymeric chain.

Examples of cyclic olefins that may be used in this polymerizationprocess include norbornene, cyclobutene, norbornadiene, cyclopentene,dicyclopentadiene, cycloheptene, cyclooctene, 7-oxanorbornene,7-oxanorbornadiene, cyclooctadiene and cyclododecene.

The polymerization reaction is generally carried out in an inertatmosphere by dissolving a catalytic amount of a carbene catalyst in asolvent and adding a cyclic olefin, optionally dissolved in a solvent,to the carbene solution. Preferably, the reaction is agitated (e.g.,stirred). The progress of the reaction can be monitored by standardtechniques, e.g., nuclear magnetic resonance spectroscopy.

Examples of solvents that may be used in the polymerization reactioninclude organic, protic, or aqueous solvents which are inert under thepolymerization conditions, such as: aromatic hydrocarbons, chlorinatedhydrocarbons, ethers, aliphatic hydrocarbons, alcohols, water, ormixtures thereof. Preferred solvents include benzene, toluene, p-xylene,methylene chloride, dichloroethane, dichlorobenzene, chlorobenzene,tetrahydrofuran, diethylether, pentane, methanol, ethanol, water, ormixtures thereof. More preferably, the solvent is benzene, toluene,p-xylene, methylene chloride, dichloroethane, dichlorobenzene,chlorobenzene, tetrahydrofuran, diethylether, pentane, methanol,ethanol, or mixtures thereof. Most preferably, the solvent is toluene ora mixture of benzene and methylene chloride. The solubility of thepolymer formed in the polymerization reaction will depend on the choiceof solvent and the molecular weight of the polymer obtained.

Under certain circumstances, no solvent is needed.

Reaction temperatures can range from 0° C. to 100° C., and arepreferably 25° C. to 45° C. The ratio of catalyst to olefin is notcritical, and can range from 1:5 to 1:30,000, preferably 1:10 to1:6,000.

Because the carbene compounds mentioned above are stable in the presenceof alcohol, thiol, ketone, aldehyde, ester, ether and halogen functionalgroups, these carbene compounds may be used to catalyze a wide varietyof reaction substrates. The added stability also enables one to employthese catalysts in the presence of a protic solvents. This is veryunusual among metathesis catalysts and provides a distinct advantage forthe process of this invention over the processes of the prior art Otheradvantages of the polymerization process of this invention derive fromthe fact that the carbene compounds are well-defined, stable Ru or Oscarbene complexes providing high catalytic activity. Using suchcompounds as catalysts allows control of the rate of initiation, extentof initiation, and the amount of catalyst.

The high level metathesis activity of the carbene compounds also makethese compounds useful for catalyzing the ring-closing metathesis ofacyclic dienes as described in Fu, G., et al., J. Am. Chem. Soc. 1993,115:9856-9858 which is incorporated herein by reference. In thering-closing reaction, the diene may contain a functional group selectedfrom alcohol, thiol, ketone, aldehyde, ester, ether, amine, amide, nitroacid, imine, carboxylic acid, disulfide, carbonate, isocyanate,carbodiimide, carboalkoxy and halogen.

The carbene compounds may also be used for the preparation of telechelicpolymers. Telechelic polymers are macromolecules with one or morereactive end-groups. Telechelic polymers are useful 30 materials forchain extension processes, block copolymer synthesis, reaction injectionmolding, and network formation. Uses for telechelic polymers and theirsynthesis is described in Goethals, Telechelic Polymers: Synthesis andApplications (CRC Press: Boca Raton, Fla., 1989).

For most applications, a highly functionalized polymer, i.e., a polymerwhere the number of functional groups per chain is 2 or greater, isrequired. Thus, it is desirable that the catalyst used to form thetelechelic polymer be stable in the presence of functional groups.

The reaction scheme for a ROMP telechelic polymer synthesis is providedbelow. In a ROMP telechelic polymer synthesis, acyclic olefins act aschain-transfer agents to regulate the molecular weight of polymersproduced. When α,ω-difunctional olefins are employed as chain-transferagents, difunctional telechelic polymers can be synthesized. As shown inthe reaction sequence, the chain-transfer reaction with a symmetric,α,ω-difunctional olefin, the propagating alkylidene is terminated with afunctional group, and the new functionally substituted alkylidene reactswith a monomer to initiate a new chain. This process preserves thenumber of active catalyst centers and leads to symmetric telechelicpolymers with a functionality that approaches 2.0. ##STR6## The onlypolymer end-groups that do not contain residues from the chain-transferagent are those from the initiating alkylidene and the end-cappingreagent. In principle, these end-groups could be chosen to match theend-group from the chain-transfer agent.

Ring opening metathesis polymerization (ROMP) using W(CHAr)(NPh) OCCH₃(CF₃)₂ !₂ (THF) has been shown to be a viable polymerization techniquefor well-defined telechelic polymers. Hillmyer, et al., Macromolecules,1993, 26:872. However, use of this carbene catalyst for telechelicpolymer synthesis is limited by the instability of the tungsten catalystin the presence of functional groups. The tungsten catalyst is alsounstable in the presence of low concentrations of monomers.

The stability of the carbene compounds of the present invention to awide range of functional groups as well as the ability of these carbenecompounds to catalyze ROMP reactions make these compounds particularlydesireable for the synthesis of telechelic polymers. The high levelmetathesis activity of the carbene compounds enable a wider range ofcyclic and acyclic olefins to be employed. By way of example, thesynthesis of hydroxytelechelic polybutadiene is described in Example 5.

The following examples set forth the synthesis and application of theruthenium and osmium carbene compounds of the present invention. Thefollowing examples also set forth the preferred embodiments of thepresent invention. Further objectives and advantages of the presentinvention other than those set forth above will become apparent from theexamples which are not intended to limit the scope of the presentinvention.

The abbreviations Me, Ph, ^(i) Pr, Cy and THF used in the followingexamples refer to methyl, phenyl, isopropyl, cyclohexyl andtetrahydrofuran, respectively.

EXAMPLES

1. One Step Synthesis of Carbene Compounds of the Present Invention

The carbene compounds of the present invention may be prepared in a onestep synthesis as illustrated in the reaction sequence below. ##STR7##

In a typical reaction, (Cymene)RuCl₂ !₂ dimer complex (0.53 g, 1.73 mmolRu) and PCy₃ (0.91 g, 2 equiv) were loaded under inert atmosphere into a100 mL Sclenk flask equipped with a magnetic stirbar. Benzene (40 mL)was then added followed by 3,3-diphenylcyclopropene (0.33 g, 1 equiv).The reaction flask was then attached to a reflux condenser under aninert atmosphere and heated in an oilbath at 83-85° C. for 6 hours. Thesolvent was then removed to complete dryness in vacuo and the remainingred solid washed with pentane (4×25 mL) under inert atmosphere. Theremaining red powder was dried under vacuum for 12 h and stored under aninert atmosphere yielding 1.4 g of Cl₂ Ru(PCy₃)₂ (═CCH═CPh₂) in 88%yield.

2. Effect of Secondary Alkyl Substituents on Catalyst Turnover Rate

The activity of the carbene catalysts of the present invention have beenfound to be proportional to the number of secondary alkyl or cycloalkylsubstituents on the phosphine. For example, in the reaction

    ______________________________________    1 #STR8##    2 #STR9##           PR.sub.3                 Relative rate    ______________________________________           P.sup.i Pr.sub.3                 3.2           P.sup.i Pr.sub.2 Ph                 1.0           P.sup.i PrPh.sub.2                 0.0    ______________________________________

the turnover rate per hour of the catalyst increases as the number ofisopropyl substituents on the phosphine increases.

                                      TABLE 1    __________________________________________________________________________    Catalytic Ring-Closing Metathesis of Dienes    (2-4 mol %  Ru!, C.sub.6 H.sub.6, 20° C.)                                                  time                                                      yield    entry  substrate             product          (hours)                                                      (%)    __________________________________________________________________________    1 2      X = CF.sub.3 Ot-Bu           3 #STR10##                                 1 #STR11##       1 1 93 91           4 #STR12##                                 2 #STR13##       1   89    4 5 6       n = 0 1 2           5 #STR14##                                 3 #STR15##        22 6 40                                                       78 93 81    7           6 #STR16##                                 4 #STR17##       2   84    8           7 #STR18##                                 5 #STR19##       5   86    9           8 #STR20##                                 6 #STR21##       8   72    10           9 #STR22##                                 7 #STR23##       1   87    11           0 #STR24##                                 8 #STR25##       2   85    __________________________________________________________________________

3. Ring-Closing Metathesis of Functionalized Dienes

Table 1 depicts the synthesis of several cycloalkenes fromfunctionalized dienes using Cl₂ Ru(PCy₃)₂ (═CCH═CPh₂) wherein Cy iscyclohexyl. A typical experimental protocol for performing ring-closingmetathesis on the diene of entry 8 of Table 1 is as follows.

The diene of entry 8 (0.50 mmol) was added to a homogeneous orange-redsolution of 0.01 mmol Cl₂ Ru(PCy₃)₂ (═CCH═CPh₂) in 15 mL of dry benzeneunder argon. The resulting mixture was then stirred at 20° C. for 5 h,at which time thin layer chromatography showed the reaction to becomplete. The reaction was then quenched by exposure to air (untilgreenish-black, 6 h), concentrated and purified by flash chromatography(0->6% Et₂ O/hexane) to yield dihydropyran as a colorless oil in 86%yield.

4. Carbene Catalyzed Polymerization of 5-Acetoxy-cyclooctene

The carbene compounds of the present invention may be used in thepolymerization of nonstrained cyclic olefins such as cyclooctene asdepicted in the reaction sequence below. ##STR26## In order topolymerize 5-acetoxy-cyclooctene, a small vial was charged with 2.6 g ofdegassed 5-acetoxy-cyclooctene and a stirbar. A solution of 15 mg of Cl₂Ru(PCy₃)₂ (═CCH═CPh₂) in 200 μL of CH₂ Cl₂ was added to the vial underinert atmosphere. The vial was capped and placed in an oil bath at about48° C. After about 2.5 hours, the red-orange solution became noticeablyviscous. After about 5.5 hours, the contents of the vial were solid.After 24 hours, the vial was removed from the oil bath and cooled toroom temperature. The cap was removed from the vial and 100 μL of ethylvinylether, 10 mL of chloroform and about 10 mg of2,6-di-tert-butyl-4-methylphenol (butylated hydroxytoluene) were addedto the vial to dissolve the solid, yielding a yellow-orange solution.After about 12 hours of stirring, an additional 20 mL of chloroform wasadded to the solution. The resulting solution was then poured into about200 mL of methanol yielding an off-white precipitate. The off-whitesolid was stirred in the methanol until it appeared free of color. Theresulting white solid was then isolated and dried under vacuum in 85%yield (2.2 g).

5. Synthesis of Hydroxytelechelic Polybutadiene.

The carbene compounds may also be used to synthesize telechlic polymerssuch as hydroxytelechelic polybutadiene as described below. A one-neck,500 mL, Schlenk flask, equipped with a magnetic stirbar, was chargedwith 1,5-cyclooctadiene (103.3 g, 955 mmol, 3673 equiv). Toluene (103.1g) and 1,4-diacetoxy-cis-2-butene (11.4 g, 66.2 mmol, 255 equiv) wereadded to the reaction flask. A stopcock was placed in the neck of theflask and the reaction mixture was stirred, cooled to 0° C., andsubjected to vacuum (˜0.05 mm Hg) at 0° C. for 30 minutes. The reactionmixture was back-filled with argon, and with a continuous argon flow,Cl₂ Ru(PCy₃)₂ (CHCHCPh₂) (0.245 g, 0.26 mmol, 1.0 equiv) was added as asolid to the reaction flask while stirring. The stopcock was replaced bya septum, and the system was subjected to vacuum (˜0.05 mm Hg) at 0° C.for 10 minutes. The dark red-orange reaction mixture was placed in anoil bath at 45-50° C. and stirred for 44 h under a slow purge of argon.The light orange reaction mixture was allowed to warm to roomtemperature. Vinyl acetate (14 g, 15 mL, 163 mmol, 627 equiv) and BHT(2,6-di-tert-butyl-4-methylphenol) (15 mg) were added to the reactionmixture under argon. The mixture was stirred at room temperature for 0.5h, placed in an oil bath at 45-50° C., and stirred for 7 h. The reactionmixture was allowed to cool to room temperature and poured into 800 mLof methanol. The mixture was stirred overnight and the polymer wasisolated by centrifugation. The polymer was then redissolved in 400 mLtetrahydrofuran, cooled to 0° C. and 100 mL of 0.7 M sodium methoxide inmethanol (70 mmol sodium methoxide) was added at 0° C. The mixture wasallowed to stir at 0° C. for 3.5 h. Methanol (400 mL) was then added tothe reaction mixture to precipitate the polymer. The reaction mixturewas allowed to warm to room temperature, stirred overnight, and isolatedby centrifugation.

6. Metathesis of Methyl Oleate

In a nitrogen-filled glove box, methyl oleate (3.2 g, 2000 equiv) wasadded to a vial containing a solution of Cl₂ (PCy₃)₂ Ru═CH--CH═CPh₂ (5mg in 0.1 mL CH₂ Cl₂). The vial was then capped and stirred at roomtemperature for 4 days. As illustrated in the reaction sequence below,an equilibrium mixture of metathesis products was produced. ##STR27##

7. Metathesis of Oleic Acid

In a nitrogen-filled glove box, oleic acid (0.3 g, 200 equiv) was addedto a vial containing a solution of Cl₂ (PCy₃)₂ Ru═CH--CH═CPh₂ (5 mg in0.1 mL CH₂ Cl₂). The vial was then capped and stirred at roomtemperature for 4 days. As illustrated in the reaction sequence below,an equilibrium mixture of metathesis products was produced. ##STR28##

8. Metathesis of Methyl Oleate and Ethylene

In a nitrogen-filled glove box, methyl oleate (1 g, 152 equiv) was addedto a Fisher-Porter tube containing a solution of Cl₂ (PCy₃)₂Ru═CH--CH═CPh₂ (20 mg in 30 mL CH₂ Cl₂). The tube was sealed,pressurized to 100 psi of ethylene, and then let stirred at roomtemperature for 12 hours. As illustrated in the reaction sequence below,an equilibrium mixture of metathesis products was produced. ##STR29##

9. Metathesis of Oleic Acid and Ethylene

In a nitrogen-filled glove box, oleate acid (0.91 g, 300 equiv) wasadded to a Fisher-Porter tube containing a solution of Cl₂ (PCy₃)₂Ru═CH--CH═CPh₂ (10 mg in 150 mL CH₂ Cl₂). The tube was sealed,pressurized to 100 psi of ethylene, and then let stirred at roomtemperature for 12 hours. As illustrated in the reaction sequence below,an equilibrium mixture of metathesis products was produced. ##STR30##

10. Depolymerization of an Unsaturated Polymer with Ethylene

In a nitrogen-filled glove box, the unsaturated polymer shown below (0.3g) was added to a Fisher-Porter tube containing a solution of Cl₂(PCy₃)₂ Ru═CH--CH═CPh₂ (20 mg in 5 mL CH₂ Cl₂). The tube was sealed,pressurized to 60 psi of ethylene, and then let stirred at roomtemperature for 24 hours. As illustrated in the reaction sequence below,an equilibrium mixture of 1,8-nonadiene and its ADMET oligomers wasproduced. ##STR31##

11. Synthesis of 1,6-Heptadiene From Cyclopentene

In a nitrogen-filled glove box, cyclopentene (1 g, 680 equiv) was addedto a Fisher-Porter tube containing a solution of Cl₂ (PCy₃)₂Ru═CH--CH═CPh₂ (20 mg in 5 mL CCl₄). The tube was sealed, pressurized to60 psi of ethylene, and then let stirred at room temperature for 24 h.As illustrated in the reaction sequence below, an equilibrium mixture of1,7-heptadiene and its ADMET oligomers was produced. ##STR32##

12. Ruthenium Carbene Catalyzed Polymerization of Dicyclopentadiene

A small Schlenk flask equipped with a small magnetic stir bar wascharged with about 9.7 g of dicyclopentadiene (DCP) (Aldrich, 95%,inhibited with 200 ppm p-tert-butylcatechol (catalog # 11,279-8)). Theflask was stoppered with a greased ground glass stopper and placed in anoil bath at about 38° C. The DCP flask was subjected to vacuum (areduced pressure of about 0.05 mmHg) and stirred for 30 minutes. Next,the flask was cooled to about 0° C. in an ice water bath for 5 minutesafter which the DCP was solid. The flask was then back-filled withargon, the stopper was removed, and (PCy₃)₂ Cl₂ Ru═CH--CH═CPh₂ (20 mg)was added as a solid (no special precautions were taken to avoidatmospheric oxygen). The stopper was replaced, and the solids weresubjected to vacuum for 10 minutes at about 0° C. The flask was placedin an oil bath at about 38° C. for 5 minutes while keeping its contentsunder vacuum. During this time the DCP liquefied, and the catalystdissolved in the DCP to yield a non-viscous, red solution which appearedhomogeneous. The stir bar was removed from the bottom of the flask withthe aid of another magnet, and the temperature was raised to about 65°C. while keeping the contents of the flask under vacuum. When thetemperature of the oil bath reached about 55° C. (about 2 minutes afterthe heating was initiated), the contents of the flask becameyellow-orange and appeared to be solid. The temperature of the oil bathwas maintained at about 65° C. for 1 hour. The flask was removed fromthe oil bath, back filled with air, broken, and the solid plug ofpolymer was removed. The polymer was washed with pentane and placed inan oven at about 130° C. for 3 hours. The polymer was removed from theoven, cooled to room temperature, and weighed (8.3 g, 86%, DCP!/Ru!˜2900). (Losses due the removal of volatiles during the degassingwere not taken into account in the calculation of the yield.)

While the present invention is disclosed by reference to the preferredembodiments and examples detailed above, it is to be understood thatthese examples are intended in an illustrative rather than limitingsense, as it is contemplated that many modifications within the scopeand spirit of the invention will readily occur to those skilled in theart and the appended claims are intended to cover such variations.

What is claimed is:
 1. A process for cyclizing a diene or modifieddiene, the process comprising contacting a diene or modified diene witha compound of the formula ##STR33## wherein: M is selected from thegroup consisting of Os and Ru;R and R¹ are independently selected fromthe group consisting of hydrogen and a substituent group selected fromthe group consisting of C₁ -C₂₀ alkyl, C₂ -C₂₀ alkenyl, C₂ -C₂₀ alkynyl,C₂ -C₂₀ alkoxycarbonyl, aryl, C₁ -C₂₀ carboxylate, C₁ -C₂₀ alkoxy, C₂-C₂₀ alkenyloxy, C₂ -C₂₀ alkynyloxy and aryloxy, the substituent groupoptionally substituted with a moiety selected from the group consistingof C₁ -C₅ alkyl, halogen, C₁ -C₅ alkoxy, and phenyl, the phenyloptionally substituted with a moiety selected from the group consistingof halogen, C₁ -C₅ alkyl, and C₁ -C₅ alkoxy; X and X¹ are anionicligands; and L and L¹ are Independently selected from PR³ R⁴ R⁵, whereinR³ is selected from the group consisting of neophyl, secondary alkyl andcycloalkyl and wherein R⁴ and R⁵ are independently selected from thegroup consisting of aryl, neophyl, C₁ -C₁₀ primary alkyl, secondaryalkyl and cycloalkyl.
 2. The process according to claim 1 wherein R³, R⁴and R⁵ are independently selected from the group consisting of neophyl,secondary alkyl and cycloalkyl.
 3. The process according to claim 2,wherein R³, R⁴ and R⁵ are independently selected from the groupconsisting of isopropyl, isobutyl, sec-butyl, neopentyl, neophyl,cyclopentyl and cyclohexyl.
 4. The process according to claim 1 whereinL and L¹ are independently selected from the group consisting ofP(isopropyl)₃, P(cyclopentyl)₃ and P(cyclohexyl)₃.
 5. The processaccording to claim 1, wherein the modified diene contains a functionalgroup selected from the group consisting of alcohol, thiol, ketone,aldehyde, ester, ether, amine, amide, nitro acid, imine, carboxylicacid, disulfide, carbonate, isocyanate, carbodiimide, carboalkoxy andhalogen.
 6. The process according to claim 5, wherein the functionalgroup is incorporated as a substituent of the modified diene.
 7. Theprocess according to claim 5, wherein the functional group isincorporated as a part of a carbon chain of the modified diene.
 8. Theprocess according to claim 1, wherein the process is conducted without asolvent.
 9. The process according to claim 1, wherein the process isconducted in a solvent selected from the group consisting of proticsolution, aqueous solution, organic solution, and mixtures thereof. 10.A process for cyclizing a diene or modified diene, the processcomprising contacting a diene or modified diene with a compound of theformula ##STR34## wherein: M is selected from the group consisting of Osand Ru;R and R¹ are independently selected from the group consisting ofhydrogen and a first substituent group selected from the groupconsisting of vinyl, C₁ -C₁₀ alkyl, aryl, C₁ -C₁₀ carboxylate, C₂ -C₁₀alkoxycarbonyl, C₁ -C₁₀ alkoxy, and aryloxy; the first substituent groupoptionally substituted with a moiety selected from the group consistingof C₁ -C₆ alkyl, halogen, C₁ -C₅ alkoxy, and phenyl; the phenyloptionally substituted with a moiety selected from the group consistingof halogen, C₁ -C₅ alkyl, and C₁ -C₅ alkoxy; X and X¹ are independentlyselected from the group consisting of halogen, hydrogen, diketonates,and a second substituent group selected from the group consisting of C₁-C₂₀ alkyl, aryl, C₁ -C₂₀ alkoxide, aryloxide, ₂ -C₂₀ alkoxycarbonyl,arylcarboxylate, C₁ -C₂₀ carboxylate, arylsulfonate, C₁ -C₂₀alkylsulfonate, C₁ -C₂₀ alkylthio, C₁ -C₂₀ alkylsulfonyl, and C₁ -C₂₀alkylsulfinyl; the second substituent group optionally substituted witha moiety selected from the group consisting of C₁ -C₅ alkyl, halogen, C₁-C₅ alkoxy, and phenyl; the phenyl optionally substituted with a moietyselected from the group consisting of halogen, C₁ -C₅ alkyl, and C₁ -C₆alkoxy; and L and L¹ are trialkyl phosphine ligands, wherein at leastone of the alkyl groups is selected from the group consisting ofneophyl, secondary alkyl and cycloalkyl.
 11. The process according toclaim 10, wherein;R and R¹ are Independently selected from the groupconsisting of hydrogen and a first substituent group selected from thegroup consisting of vinyl, C₁ -C₅ alkyl, phenyl, C₂ -C₅ alkoxycarbonyl,C₁ -C₅ carboxylate, C₁ -C₅ alkoxy, and phenoxy; the first substituentgroup optionally substituted with a moiety selected from the groupconsisting of C₁ -C₅ alkyl, halogen, C₁ -C₅ alkoxy and phenyl; thephenyl optionally substituted with a moiety selected from the groupconsisting of halogen, C₁ -C₅ alkyl and C₁ -C₅ alkoxy; and X and X¹ areindependently selected from the group consisting of Cl, Br, I, and asecond substituent group selected from the group consisting of benzoate,acetylacetonate, C₁ -C₅ carboxylate, C₁ -C₅ alkyl, phenoxy, C₁ -C₅alkoxy, C₁ -C₅ alkylthio, aryl, and C₁ -C₅ alkyl sulfonate; the secondsubstituent group optionally substituted with a moiety selected from thegroup consisting of halogen, C₁ -C₅ alkyl and phenyl; the phenyloptionally substituted with a moiety selected from the group consistingof halogen, C₁ -C₅ alkyl and C₁ -C₅ alkoxy.
 12. The process according toclaim 4, wherein:R and R¹ are independently selected from the groupconsisting of vinyl, H, Me, and Ph; and X and X¹ are independentlyselected from the group consisting of Cl, CF₃ CO₂, CH₃ CO₂, CFH₂ CO₂,(CH₃)₃ CO, (CF₃)₂ (CH₃)CO, (CF₃) (CH₂)₂ CO, PhO, MeO, EtO, tosylate,mesylate, and trifluoromethanesulfonate.
 13. The process according toclaim 10, wherein the alkyl groups of the trialkyl phosphine ligands areindependently selected from the group consisting of neophyl, secondaryalkyl and cycloalkyl.
 14. The process according to claim 13, wherein thealkyl groups of the trialkyl phosphine ligands are independentlyselected from the group consisting of isopropyl, isobutyl, sec-butyl,neopentyl, neophyl, cyclopentyl and cyclohexyl.
 15. The processaccording to claim 10, wherein L and L¹ are independently selected fromthe group consisting of P(isopropyl)₃, P(cyclopentyl)₃ andP(cyclohexyl)₃.
 16. The process according to claim 10, wherein themodified diene contains a functional group selected from the groupconsisting of alcohol, thiol, ketone, aldehyde, ester, ether, amine,amide, nitro acid, carboxylic acid, disulfide, carbonate, carboalkoxyacid, isocyanate, carbodiimide, carboalkoxy, and halogen.
 17. A processaccording to claim 10, wherein the process is conducted without asolvent.
 18. A process according to claim 10, wherein the process isconducted in a solvent selected from the group consisting of proticsolution, aqueous solution, organic solution, and mixtures thereof. 19.A process according to claim 10, wherein the diene Is selected from thegroup consisting of 1,6-dienes, 1,7-dienes, and 1,8-dienes and themodified diene is selected from the group consisting of modified1,6-dienes, modified 1,7-dienes, and modified 1,8-dienes.
 20. A processfor diene or modified diene cyclization, the process comprisingcontacting a diene or modified diene with a compound selected from thegroup consisting of ##STR35## wherein Cy is cyclohexyl or cyclopentyland Pr^(i) is isopropyl.
 21. The process according to claim 20, whereinthe modified diene contains a functional group selected from the groupconsisting of alcohol, thiol, ketone, aldehyde, ester, other, amine,amide, nitro acid, carboxylic acid, disulfide, carbonate, carboalkoxyacid, isocyanate, carbodiimide, carboalkoxy, and halogen.
 22. Theprocess according to claim 21, wherein the functional group isincorporated as a substituent of the modified diene.
 23. The processaccording to claim 21, wherein the functional group is incorporated as apart of a carbon chain of the modified diene.
 24. The process accordingto claim 20, wherein the process is conducted without a solvent.
 25. Theprocess according to claim 20, wherein the process is conducted in asolvent selected from the group consisting of protic solution, aqueoussolution, organic solution and mixtures thereof.
 26. The processaccording to claim 20 wherein, the diene is an α,ω-diene and themodified diene is a modified α,ω-diene.
 27. The process according toclaim 26, wherein the diene is selected from the group consisting of1,6-dienes, 1,7-dienes, and 1,8-dienes and the modified diene isselected from the group consisting of modified 1,6-dienes, modified1,7-dienes, and modified 1,8-dienes.